One the latest trends in “green” living is rain harvesting. Tanks and downspouts are appearing on houses and commercial buildings all over the Southwest and beyond to capture this precious, temporary resource. As is often the case, Nature shows us that no idea is really new.
An early practitioner of rain harvesting is the humble “horny toad” or, more properly, horned lizard. In 1990, Wade Sherbrooke, then director of the Southwestern Research Station of the American Museum of Natural History near Portal, Arizona, observed that captive Texas Horned Lizards exhibited stereotyped behavior during rainstorms. The lizard would raise its abdomen in an arch, splay and extend its legs, and flatten its body. Rainwater striking its back flows by capillary action in the spaces between the scales to the corners of the mouth, where the lizard is able to drink it. A similar but unrelated lizard in Australia, the Thorny Devil, also does rain harvesting, an example of convergence.
The Texas Horned Lizard mentioned in the study is one of eight species of horned lizards that live in the United States. Their genus name, Phrynosoma, means “toad-bodied,” an apt description of their less-than-sleek physique. Perhaps the increase in surface area for rain harvesting is one advantage of this unusual shape.
This summer we have seen the lovely Regal Horned Lizard (shown in the photo) in our driveway near a colony of her favorite prey, Harvester Ants. Horned lizards feed almost entirely on ants, and we are glad to have this amazing lizard as part of a natural ant control program.